Grid-controlled electric vacuum discharge apparatus



Feb. 11, 1936; J. VON ISSENDORFF 3 GRID CONTROLLED ELECTRIC VACUUM DISCHARGE APPARATUS Filed April 1, 1933 WITNESSES: INVENTOR ,ATTORNEY 4211 7 Jz'iryen van Issendorff 5% mmww Patented Feb. 11, 1936' 2,030,127

UNITED STATES PATENT OFFICE GRID-CONTROLLED ELECTRIC VACUUM DISCHARGE APPARATUS Jiirgen von Issendorff, Berlin- Siemensstadt, Germany, assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application April 1, 1933, Serial No. 663,938 In Germany April 6, 1932 5 Claims. (Cl. 175-363) My invention relates to grid-controlled elecwill be preferable in many cases to be able to trlc vacuum discharge apparatus for the statical completely control the quenching process as for conversion of electrical power into alternating instance to increase the stability of the oscillacurrent. tions, A cessation of these oscillations would gen- In the fundamental connection for the producerally result in a short circuit of the D. C. source. tion of alternating current, particularly of high According 'to the present invention the above frequency, from direct current by means of gasmentioned drawbacks are overcome in that the or vapor-filled grid-controlled electric discharge charging currents for the commuating condenser device a condenser is inserted which is of parenergized at the frequency of the alternating ticular importance for the operation of the apcurrent, are conducted through additional valves paratus. The main object of this condenser is to which are controlled in part or in whole and are provide for a periodical extinction of the operatafiected thereby. ing discharge in the valves by means of instanta- Fig. 1 is a schematic illustration of a valve neous absorption of the discharge current, the type converter having a capacitor for commutatvalve under consideration being blocked each ing the valves. time by a negative grid potential. The condenser Fig. 2 is a similar view showing an improv is discharged during an extinction and is charged control system according to my invention.

thereafter in opposite direction so that the con- In Fig. 1 is illustrated an embodiment showdenser possesses the right polarity for extinguishing how the electric discharge valves for the proing the succeeding valve or anode arc. Another duction of alternating current from direct curobject of the condenser is to supply wattless current have been hitherto connected. The directrent to the transformer whereby the wave form of current conductor I is connected with the center the supplied alternating current approaches the of a primary winding 6 of a transformer 8, the sine shape. The latter object of the condenser ends of which are connected with the controlled is, however, of less importance than the firstvalves 4 and 5. The direct-current conductor 2 named, since the apparatus may readily supply is connected to the cathodes of both electric either leading or lagging wattless current to the valves 4 and 5 through an inductance 3. The alternating current circuit, 1. e., energy to capacialternating current conductors are connected to tlve or inductive consuming devices. the secondary winding 1 of the transformer 8. It is a fundamental characteristic of this sys- The commutating condenser 9 is inserted between tem that it will permit the occurrence of tripping the two electrodes supply conductors of the prior unbalanced oscillations, which can change into mary winding 6 of the transformer 8. In this conharmonic oscillations in only special cases. Un nection the above described drawbacks result.

balanced and non-uniform oscillations will be An embodiment of my invention is shown in 5, present if the A. C. energy translating device Fig. 2. Also in this figure the parts correspondcomprises mainly inductive elements. ing to Fig. 1 are denoted by the same numerals If the A. C. circuit contains in addition a sine of reference. However, in this case the conshaped E. M. R, which may be produced by a denser 9 is connected to the terminals of the synchronous generator, then this E. M F. will winding 6 through non-controlled valves I5 and ube impressed on the transformer and on the con- 16. These valves are opposing and would, theredenser. We may hereinafter term this condenser fore, not permit alone any change of charge. A a commutating condenser. Of course the syschange of charge is only possible if one of the tem will lose the property of generating independcontrolled valves II or I8 cooperates therewith, ent tripping oscillations, and in connection therewhich may be controlled in common, i. e., nearly 5 with also the capacity of delivering wattless curat the same time with the valves 4 or 5. By rents into the A. C. circuit. The quenching conthe ignition of the arc in the valve It! a denser alone has the capacity to do this, but only charging current flows through the valve l5 and toalimited extent which isingeneral insuflicient. quenches the discharge in the main valve 4, The rest of the wattless currents would then have so that the valve 5 operates in a corresponding 0 to be provided by the synchronous generator manner as in the case of Fig. 2. In the connecwhich would then operate as a phase shifting detion disclosed, an auxiliary transformer I9 is convice, so that it could deliver a smaller amount of nected to the terminals of the condenser 9 for a rgy, improving and relieving the auxiliary valves l5, But even if there is no independent alternating l6, l1 and IS in order that the condenser may be 5 current E. M. F. in the circuit being energized, it charged in the desired manner. To this end,

the transformer I9 is connected to the terminals of the winding 5 of the transformer 8 through an ohmic, inductive or capacitive resistance 20.

V In case the controlled valves 4 and 5 have, as disclosed, reversed polarity the auxiliary valves would have to be also inserted with reversed polarity. The control voltages may be supplied by the transformer 8 in a suitable phase displacement in a well-known manner or may be controlled by the mechanical method in part, for instance, by a contact drum or by an oscillatory impulse transmitter. The direct current flowing through the conductors I and 2 may in case of necessity be supplied by a corresponding rectifier.

Alternating current may, however, also be directly supplied to the valves to be arranged in a multiple manner, for instance, to the valves 4 and 5 so that the described inverter is changed into a static frequency changer. If the supplied electrical power is, for instance, present in the form of three-phase current, the valves 4 and 5 may be also carried out as three or multi-anode rectifiers. Instead of the individual valves, multianode rectifiers may also be employed, if the cathodes of the valves have the same potential.

If an m-phase current is desired instead of the produced single-phase alternating current, the connection must also be carried out with m or 2m phases by arranging besides the main electric valves, also the auxiliary valves at least in a mfold manner. The quenching transformer, however, must not absolutely be multiplied m times if the terminals thereof are, for instance, connected to each phase terminal of the winding 6 through two controllable valves connected in parallel and in opposite relation to one another.

For avoiding too high discharging surges of the quenching condenser it is advisable to insert between the terminals of the winding 6 and the valves reactors corresponding to the wellknown anode reactors or to connect a reactor in series with the condenser. Resistances for damping oscillations are also used to a slight extent.

I claim as my invention:

1. An apparatus for statically converting electrical power into alternating current of any frequency having in combination a direct-current source, a transformer, a plurality of main gridcontrolled arc valves, a commutating condenser interconnected between the conductors of the primary winding of said transformer so as to be impressed with frequency of the produced alternating current, noncontrolled auxiliary electric valves connected between the conductors of the primary winding of said transformer .and the condenser, other grid-controlled valves connected between the direct-current source and each side of the condenser and an auxiliary transformer connected across the condenser to charge the same independently of said auxiliary valves.

2. An apparatus for statically converting electrical power into alternating current of any frequency having in combination a direct-current source, a transformer, a plurality of main gridcontrolled arc valves, a commutating condenser interconnected between the conductors of the primary winding of said transformer so as to be impressed with frequency of the produced alternating current, non-controlled auxiliary electric valves connected between the conductors of the primary winding of said transformer and the condenser, other grid-controlled valves arranged between the direct-current source and the condenser, an auxiliary transformer connected across the condenser for charging the condenser independently of said auxiliary valves and connected to the first-named transformer, and a resistance inserted between said auxiliary transformer and the primary winding of the first-named transformer.

3. A vapor electric converter comprising a direct current supply line, an alternating current load line, an inductive winding associated with alternating current line and one side of the direct current line, a plurality of controlled main valves connected between said winding and the opposite side of the direct current line, an auxiliary transformer fed by said inductive winding, a commutating capacitor charged by said transformer, a resistor in series with the primary of said transformer for controlling the charge on said capacitor and auxiliary valves for discharging said capacitor to commutate said main valves.

4. A vapor electric converter comprising a direct current supply line, an alternating current load line, an inductive winding associated with said alternating current line and one side of the direct current line, a plurality of controlled main valves connected between said winding and the opposite side of the direct current line, an auxiliary transformer fed by said inductive winding, a commutating capacitor charged by said transformer, means in series with said transformer for controlling the charge on said capacitor, oppositely connected valves between opposite sides of said capacitor and the anode leads of said main valves and controlled valves connected between opposite sides of said capacitor and the cathode side of said main valves.

5. A conversion system comprising an alternating current load system, a supply system, a transformer connected to said load system and said supply system, a plurality of controlled main valves for regulating the flow of current between said systems, an auxiliary transformer connected to said first mentioned transformer,

a commutating capacitor connected to said auxiliary transformer, means in series with said auxiliary transformer for controlling the charge on said capacitor, controlled auxiliary valves connected from opposite sides of said capacitor to one side of said main valves and oppositely disposed valves for connecting said capacitor to the anode leads of said main valves.

J URGEN VON ISSENDORFF. 

